As parents, we watch for our children to begin crawling and walking. As they grow, we wait to see them reach other milestones in movement, such as throwing, catching, jumping, and skipping.
It’s understood that children need to be developmentally ready before they can perform these different movement skills. They can’t do these things if their nervous system and muscles haven’t developed enough to provide the necessary coordination and strength. This concept of readiness is pretty easy to grasp.
Less understood is the concept of sensitive periods of development, and this is equally important.
What are sensitive periods?
Sensitive periods are times when particular physical and cognitive capacities in children are especially active in their development, such as speech and vision in early infancy and childhood. During these periods, any active stimulation of these potential capacities produces quick adaptation and improvement.
As children grow, research suggests there are sensitive periods for other physical capacities as well. The best examples are stamina and strength. Done at the right times, active “training” of these capacities produces better results. Prior to these times, it does very little.
The best time to develop lung capacity and aerobic endurance (stamina) is when children have entered puberty. Due to the rush of hormones and rapid growth, the lungs become more adaptable to training. Send teenagers on regular distance runs and their stamina improves a lot.
On the other hand, research shows that sending nine-year-old kids on distance runs to train their endurance essentially does nothing. Their stamina barely changes because their lungs aren’t at the right stage of physical development.
Strength development is similar. Girls and boys both make the most dramatic gains in strength after entering puberty. As prepubescent children, it’s possible to train strength and make some gains, but it relies on having proper adult supervision and working carefully within very specific limits.
The practical reality is that prepubertal children can develop all the strength they need through basic play activity such as climbing trees, swinging on monkey bars, and doing a variety of vigorous activities such as dance and sports. They don’t need to lift free weights or work out at the gym—they just need to be active on a regular basis.
Give consideration to sensitive periods
It’s worth considering sensitive periods if you’re a parent, teacher, or coach, because there’s no point trying to develop the wrong things at the wrong times.
For instance, if prepubertal children have little or no response to training stamina and strength, why waste an overabundance of time trying to develop those things? It makes better sense to focus on the physical qualities and abilities that are perhaps more responsive to training at that age, such as skill learning and the development of general physical coordination.
Everything can be trained at any age
Sensitive periods don’t imply that there is only one time to develop a particular physical quality or domain. Almost every physical capacity and ability can be trained and developed to some degree at any age. The key idea is that the sensitive periods provide more gains.
If good training happens at the right time, it can deliver big results. However, if it’s done at the wrong time, it may have little positive effect. And if it’s done particularly poorly at any age, it might even hurt the child by pushing their body beyond the physical limits of that stage of development.
The physical development of children relies largely on the natural timing of different processes of growth and maturation, which adults don’t control. This is why it’s important for parents and coaches to understand, respect, and work with the sensitive periods of development.